The compound of Formula 1 below, whose compound name is N-(3-(2-(4-(4-methylpiperazin-1-yl)phenylamino)thieno[3,2-d]pyrimidin-4-yloxy)phenyl)acrylamide {INN: 2-propenamide, N-[3-[[2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]thieno[3,2-d]pyrimidin-4-yl]oxy]phenyl]}, is disclosed in PCT application WO 2011/162515. The compound has a selective inhibitory activity for a mutant epidermal growth factor receptor tyrosine kinase

Additionally, the above reference discloses the method of preparing the compound of Formula 1.
However, the compound of Formula 1 prepared in the above cited references was prepared as an amorphous solid, which is a form generally less suitable for a large-scale production of pharmaceutical drugs. For example, the thus-prepared form of the compound of Formula 1 was insufficient in the aspects of stability and non-hygroscopicity for pharmaceutical formulations.
Accordingly, there is a need for the development of the compound of Formula 1 in crystalline forms which can fully comply with the strict requirements and details thereof regarding pharmaceutical solid forms and formulations. Additionally, the compound of Formula 1 is preferably in a form that affords facile handling of the product upon synthesis such as ease of filtration and drying, and also for the purpose of economy, preferably enables long-term stable maintenance of a crystalline form without requiring particular storage conditions.
Under these circumstances, the present inventors have made intensive efforts to develop a novel crystalline form of the compound of Formula 1, and have discovered that a particular crystalline form can provide excellent overall physicochemical properties such as stability, non-hygroscopicity, etc., and thus it can be easily used for the preparation of a pharmaceutical composition containing the same as an active ingredient, thereby completing the present invention.